Article elevating device

ABSTRACT

An article elevating device for buoyant articles and the like providing a column of liquid having predetermined upper and lower ends and an article injecting mechanism downwardly spaced from the upper end of the column for successively injecting a plurality of such articles into the column of liquid for automatic ascent through the liquid to said upper end of the column. Gas charged containers are also utilized to elevate nonbuoyant materials in a similar manner.

United States Patent Minnite 1451 Oct. 17, 1972 [54] ARTICLE ELEVATING DEVICE 3,063,079 11/ 1962 Bergman et a1 ..137/268 X [72] Inventor: Ralph Minnite, R0. BOX 198, Can- FOREIGN PATENTS OR APPLICATIONS tua Creek, Calif. 93608 637,817 4/1962 Italy ..114/16.7 [221 July 30,1970 1,071,942 9/1954 France ..209/173 [21] Appl. No.: 59,655

Primary ExaminerEvon C. Blunk Assistant Examiner-W. Scott Carson [52] US. Cl. ..209/173, 114/16.7, 137/268, Attorney Huebner & worm] 302/2 R, 302/15 [51] Int. Cl. ..B03b 3/38, B63g 8/40 57 ABSTRACT [58] Field of Search ...1 14/165, 16.6, 16.7; 137/268;

209/162, 173; 302 R, 1446 50 An article eleyatmg device for buoyant articles and the like providing a column of l1qu1d having predeter- [56] References Cited mined upper and lower ends and an article injecting mechanism downwardly spaced from the upper end of UNITED STATES PATENTS the column for successively injecting a plurality of such articles into the column of liquid for automatic Mox ham ascent through the to said pp end of the 2,670,078 DaVlS column. Gas charged containers are also utilized to 33223223 1111322 1iiifi.iiiiiiiijiiiiiii113111383113 a mile 3,063,080 11/1962 Bergman et a1 ..137/268 X 10 Claims, 16 Drawing Figures PATENTEDU I 7 I972 saw 1 or 3 RALPH ,4 TTO/PNEK PATENTEDnm 17 I972 SHEET 2 0F 3 PAL PH M/NN/ TE IN VE N TOP PATENTED I 7 I973 3. 698, 553

' sum 3 OF 3 RALPH M/NN/TE INVENTOP A TTORNEVS ARTICLE ELEVATING DEVICE BACKGROUND OF THE INVENTION Mechanical elevating devices, such as elevators and various types of material conveyors have long been employed in buildings, on construction projects, and in mine shafts and the like. These devices involve sophisticated, highly complicated and expensive mechanisms which require a relatively large power source. Such mechanisms further require frequent inspection and repair which may constitute a substantial safety hazard if not properly maintained. In mines, the required electrical systems for such elevating devices create a substantial hazard when employed in areas subject to development of combustible gases and the like. Small electrical sparks have been known to ignite such gases, causing dangerous mine tunnel cave-ins. Such problems can of course be overcome by eliminating the relatively high powered electrical systems presently employed. Another problem in mining operations involves the permanent installation of the primary vertical mine shafts which cannot be easily moved as the mining operation progresses farther away from the shafts. Accordingly, the horizontal mine tunnels must be shored up and maintained for relatively long distances which substantially increases the danger of cave-ins and the like. If it were possible, conveniently and economically, periodically to move the primary vertical mine shaft so as to be disposed relatively closely to the area being worked, many of the above problems and safety hazards would be eliminated.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved article elevating device.

Another object is to provide such an improved article elevating device which can be more quickly, conveniently, and economically constructed than existing powered elevating devices.

Another object is to provide an article elevating device of the character described which can be conveniently transported and installed at different locations in a minimum of time.

Another object is to provide an improved article elevating device which has relatively few moving parts and which is virtually maintenance free.

Another object is to provide an article elevating device which is adapted for a wide variety of uses with a minimum of modification.

Another object is to provide an article elevating device which utilizes a column of liquid for elevating buoyant articles with a minimum of mechanical assistance.

Another object is to provide an article elevating device which incorporates an injection mechanism continually closing the column of liquid and precluding leakage therefrom during the introduction of articles into the column ofliquid.

Another object is to provide an article elevating device which utilizes gas charged containers for elevating non-buoyant materials through the column of liquid.

Another object is to provide an article elevating device which may be readily adapted for the grading and separating of buoyant agricultural produce.

Other objects and advantages of the present invention will become more fully apparent upon reference to the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an article elevating device embodying the principles of the present invention shown in a typical installation within a mine tunnel fragmentarily indicated in a cross sectional view of the earth for elevating articles from the tunnel to the surface.

FIG. 2 is a somewhat enlarged, fragmentary cross section through the lower end of the article elevating device and an article injection mechanism associated therewith shown in an article loading position.

FIG. 3 is a somewhat enlarged, fragmentary cross section similar to FIG. 2 showing the article injection mechanism in an intermediate position prior to discharge of the article into the elevating device.

FIG. 4 is a somewhat enlarged, fragmentary cross section similar to the preceding Figures showing the article released from the injection mechanism for buoyant ascent upwardly through the column of liquid within the casing of the elevating device.

FIG. 5 is a somewhat enlarged, fragmentary cross section similar to the preceding Figures with the injection mechanism disposed in an initial position during its return to an article loading position.

FIG. 6 is a somewhat enlarged, fragmentary cross section similar to the preceding Figures showing the injection mechanism further advanced toward its article loading position.

FIG. 7 is a somewhat enlarged, fragmentary cross section similar to the preceding Figures showing the article injection mechanism in an article loading position.

FIG. 8 is a somewhat enlarged, fragmentary cross section through the article injecting mechanism incorporating an electromagnetic coupling.

FIG. 9 is a somewhat enlarged, fragmentary cross section of a second form of an electrically actuated mechanical coupling for the article transferring components thereof.

FIG. 10 is a somewhat enlarged, fragmentary cross section of the electromechanical coupling of FIG. 9 disposed in a latched position.

FIG. 11 is .a somewhat enlarged, transverse vertical section through the second form of electromechanical coupling taken on line 11-11 of FIG. 9.

FIG. 12 is a top plan view in partial horizontal section through the article elevating device of the present invention showing a second form of article injection mechanism.

FIG. 13 is a somewhat enlarged, fragmentary, longitudinal vertical section through the second form of injection device of FIG. 12.

FIG. 14 is a perspective of a gas-charged container for use with the elevating device of the present invention for elevating non-buoyant materials.

FIG. 15 is a perspective of a second form of material elevating container which is particularly adapted for buoyant material.

FIG. 16 is a perspective of a third form of material elevating container for buoyant material.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more particularly to the drawings, an article elevating device embodying the principles of the present invention is generally indicated by the reference numeral 10. As best shown in FIG. 1, the article elevating device is disposed in a representative environment consisting of a mine tunnel l 1 located a substantial distance beneath the surface 12 of the earth. The elevating device provides an elongated tubular casing 15 having predetermined upper and lower ends 16 and 17, respectively. The lower end 17 of the casing is rested upon a base 18 in closing relation to passage 20 within the casing. The passage is substantially filled with a liquid material 22 such as water or the like, to provide an article elevating column within the casing.

An article injecting mechanism, generally indicated by the reference numeral 25, is mounted in radially outwardly extended relation closely adjacent to the lower end 17 of the casing 15 within the mine tunnel 11. As best shown in FIGS. 2 through 7, such mechanism provides an elongated cylindrical outer valve housing 26 having an inner flanged end 27 extended into the casing 15 and secured thereto by a ring of bolts 28. The housing includes an opposite outer flanged end 29 for a purpose subsequently to be described. An article loading opening 30 is formed in the housing intermediate its ends and provides an upwardly extended annular funnel 32 for guiding articles into the opening.

The valve housing 26 is effective continually to close the lower end of the casing and preclude leakage of liquid 22 from the column during the article injecting operation. For this purpose, an hydraulic jack 35 is mounted on the outer end 29 of the housing by a flange 36 bolted by way ofa ring of bolts 37 in precise coaxial relation with the housing. The hydraulic jack includes an inwardly extended piston rod 38 to which is secured a valve plunger 40 slidably reciprocably disposed within the housing.

An internal valve housing 42 is disposed within the passage 20 of the casing 15 in spaced coaxial relation to the outer valve housing 26. The inner valve housing has an inner end 43 spaced a predetermined distance from the inner end 27 of the outer housing and an outer flanged end 44 extended through and bolted to the wall of the casing by a ring of bolts 45. An hydraulic jack 47 is bolted to the outer flanged end in outwardly extended coaxial relation to the inner valve housing. A piston rod 48 is inwardly concentrically extended into the inner valve housing and has mounted on the outer end thereof an elongated valve plunger 50. When the article injecting mechanism is in its loading position as shown in FIGS. 2 and 7, the distal end of the valve plunger 50 is disposed adjacent to one side of the article loading openings by full extension of the piston rod 48 and the valve plunger 40 is disposed adjacent to the opposite side of the article loading opening by substantially full retraction of its piston rod 38. At such time, the valve plunger 50 is disposed in bridging relation to an article discharging passage 55 defined between the inner ends of the outer valve housing 26 and the inner valve housing 42 in order to preclude any leakage of the liquid column 22 within the casing while buoyant articles, such as that indicated by the reference numeral 56, are inserted into the loading opening 30 in the outer valve housing.

In a particular location where space is at a premium, the hydraulic jack 47 within the inner valve housing 42 is eliminated by use of the hollow cylindrical valve plunger 60 as shown in FIG. 8. The valve plunger is actuated by an electromagnet 62 disposed in the inner end of the plunger and which includes an elongated electrical cord 64 extending through the plunger and into a flanged cup-shaped housing 66 secured to the outer periphery of the casing by a plurality of bolts 67. The housing encloses and accommodates a coiled section 68 of the cord 64 to provide sufficient surplus to accommodate reciprocal movement of the plunger across the article discharging space 55 during its movement to the article loading position of FIGS. 2 and 7 of the first form. The outer end of the cord is connected to a suitable source of electrical energy, not shown.

Alternatively, the mechanical interlock or latching device, generally indicated by the reference numeral 70 in FIGS. 9, l0 and 11, can be provided for coupling the inner ends of the valve plungers 40 and 60 during their movement to the article loading position of FIGS. 2 and 7. Such interlock is formed by an extension 72 of the piston rod 38 of the hydraulic jack 35 which is slidably extended through the valve plunger 40. The piston rod has a hooked end 74 receivable within a notch 75 in the inner end of the valve plunger 40 and which is biased to that position by a compression spring 76 positioned between the rearward end of the valve plunger and a flange 77 on the piston rod 38. Instead of the electromagnet 62, a hook receiving plug 80 is disposed in the inner end of the valve plunger 60 which has a semicircular latching groove 82 formed therein. An electrical solenoid valve 85 is disposed within the plunger immediately adjacent to the plug 80. The solenoid has a coil portion 86 pivotally secured by a bracket to the inner periphery of the plunger and an opposite reciprocating rod portion 88 pivotally mounted on the plug 80.

A second form of article injecting mechanism is generally indicated by the reference numeral 90 in FIGS. 12 and 13. This form provides a circular tube 91 providing a substantially endless cylindrical passage which extends substantially transversely through the lower end of the casing 15 in substitution for the inner and outer valve housings 42 and 26, respectively. As best shown in FIG. 13, the tube includes spaced ends 92 and 93 defining therebetween an article discharge passage 95. The end 92 is flared for a purpose subsequently to be described. An article loading opening 97 having an upwardly extended funneling flange 98 similar to the article loading opening 30 of the first form is disposed in the tubing closely adjacent to the casing 15.

A plurality of substantially cylindrical article actuating slugs 100 are disposed within the passage of the tube in substantially end-to-end abutting relation. Each of the slugs has a beveled or chamfered leading end 102 and a substantially flat trailing end 103. The slugs substantially fill the passage of the tube except to provide a pair of spaced article receiving compartments 105 and 106 respectively adjacent to the discharge passage 95 and the article loading opening 97.

The slugs 100 and the articles 56 to be elevated are actuated through the tube from the loading compartment 106 to the discharge passage 95 by a ratchet finger mechanism 110. The finger provides a shoulder 112 engageable with the flat trailing ends 103 of the slugs and an upwardly angularly disposed rearward edge 114 conforming to and adapted to be rested against the forward chamfered ends thereof. The forward end of the ratchet finger is pivotally mounted on a bracket 115 carried on the outer distal end of a piston rod 116 of an hydraulic jack 118 mounted above the tube on a mounting frame 120.

The lower end of the casing in this form, as shown in FIG. 13, provides an angularly sloped floor 122 which is adapted to receive non-buoyant articles which it is desired to separate from the articles having sufficient buoyancy to rise to the surface of the column of liquid 22 within the casing 15. An access door 125 is provided adjacent to the lowest point of the floor in order to remove such separated articles after draining the liquid 22 from the casing.

A container 130 for elevating non-buoyant materials is shown in FIG. 14. Such container is separable along its central axis and has an upper half 132 thereof providing a gas-charged chamber to afford sufficient buoyancy for the container. The container includes a lower half 134 for receiving non-buoyant material which is elevated with the container by its buoyant upper half 132.

Another form of article conveyor container 135 is shown in FIG. of similar cylindrical configuration having substantially flat imperforate end panels 136 and a perforated cylindrical wall 137 extended therebetween for receiving buoyant articles therein of sufficient buoyancy to float the container to the surface of the column ofliquid 22 in the casing 15.

A spherical wire screen container 140 is shown in FIG. 16 which is similarly adapted for constraining a plurality of buoyant articles therein for delivery to the surface of the column ofliquid 22 within the casing.

OPERATION The operation of the described embodiments of the subject invention is believed to be clearly apparent and is briefly summarized at this point. The casing 15 may be easily installed by conventional well drilling equipment to extend from the surface 12 of the ground downwardly therethrough until the lower end thereof is rested upon the floor of the mine tunnel 11 or the like. The article injecting mechanism 25 is then assembled as previously described adjacent to the lower end 17 of the casing and the passage 20 thereof substantially filled with water to provide the article elevating column of liquid 22.

As best shown in FIGS. 2 and 7, the article injecting mechanism is in a condition to receive an article through the loading opening between the valve plungers 40 and 50. It will be noted that at this time, the piston rod 38 of the hydraulic jack is substantially completely retracted and the piston rod 48 of the hydraulic jack 47 is fully extended so that the valve plunger 50 is disposed in bridging relation across the article discharge space 55 to preclude any leakage of fluid from the column 22 within the casing during the article loading operation. Suitable hydraulic controls,

not shown, are provided in connection with the hydraulic jacks 35 and 47 to provide simultaneous extension of the piston rod 38 and retraction of the piston rod 48 to move the article 56 to be elevated to the left as shown in FIG. 3 to the releasing position of FIG. 4 with the article precisely aligned within the article discharge space 55. Upon such release, the buoyant article is permitted to float upwardly through the column of liquid until reaching the surface thereof at the upper end 16 of the casing. Any non-buoyant materials which are desired to be elevated are placed in the container 130, as shown in FIG. 14, with the upper gas-charged chamber 132 thereof providing sufficient buoyancy to carry such material to the surface.

After the release of the article, as shown in FIG. 4, the hydraulic jacks 35 and 47 are deactivated to return them to the article loading position of FIGS. 2 and 7. As shown, the hydraulic jacks may be of the single action type inasmuch as only the jack 35 need be activated during the injection operation and only the jack 47 need be activated to return the valve plungers to their article loading positions. As shown in FIG. 5, the plunger 50 is effective to abut the adjacent end of the plunger 40 to shove it to the right upon extension of the piston rod 48.

When the electromagnetic valve plunger 60 of FIG. 8 is employed, the hydraulic jack 47 is completely eliminated. Accordingly, after release of the article both from between the plungers 40 and 60, the magnet is energized in order to draw the plunger 60 through the discharge space and against the distal end of the valve plunger 40. Upon subsequent actuation of the hydraulic jack 35, the plunger 40 is retracted to the loading position with the current to the electromagnet 62 being shut off upon the alignment of the leading edge of the valve plunger 60 with the loading opening 30.

The same operation occurs during the use of the mechanical interlock mechanism of FIGS. 9, l0 and 11 but which provides a positive coupling between the valve plungers 40 and 60. In this form, upon the release of the article from between the plungers through the article discharge space 55, the plunger 40 is further extended by appropriate actuation of its hydraulic jack 47 for entry of the hook end 74 of the rod extension 72 into the hook receiving groove 82 which is immediately latched by actuation of the solenoid valve 85. Such mechanism is then automatically released upon alignment of the leading edge of the plunger 60 with the opening 30 in the outer valve housing 26.

The second form of injecting mechanism 90, as shown in FIGS. 12 and 13, operates in a substantially similar manner to the preceding for m except that the slugs are continually slide in one direction upon the introduction of an article into the loading opening 97 and upon actuation of the ratchet finger by the hydraulic jack 118. Accordingly, during extension of the piston rod 116, the loaded article 56 to be elevated and the slugs are slid to the left, as viewed in FIG. 13, so that the preceding article is precisely aligned or registered with the discharge passage 95 between the ends 92 and 93 of the tube 91. Upon the return stroke of the piston rod, the ratchet finger 110 pivots upwardly and the shoulder 112 thereof is permitted to hook over the flat trailing end 103 of the next plug.

This form of the present invention is excellently suited to grading and separating non-buoyant materials which will automatically gravitate downwardly from the discharge opening and be collected upon the floor 122 of the casing. After a predetermined period of operation, such non-buoyant articles can be removed through the door 125 after first draining the liquid 22 from the casing.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved article elevating device which may be readily adapted for elevating a wide variety of buoyant and non-buoyant articles in a relatively large number of environments such as mining operations, elevating articles up relatively steep grades, and during the construction of high rise buildings and the like. The article elevating device of the present invention can be quickly, conveniently and economically constructed. it has relatively few moving parts substantially free of costly maintenance procedures after its initial installation. It is further adaptable for grading and separating buoyant agricultural produce and the like with a minimum of modification.

Although the invention has been herein shown and described in what are conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the illustrative details disclosed.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An article elevating device for buoyant articles comprising a column of liquid having predetermined upper and lower ends; and means downwardly spaced from said upper end of the column for successively injecting such articles into the column of liquid for ascent through the liquid to the upper end of the column, said means including a valve having an article loading opening outwardly spaced from said column of liquid and an article discharge opening disposed within the column of liquid with the valve continually closing the column to block leakage of liquid therefrom during injection of said articles, a pair of slidably mounted pistons reciprocable between said article loading and article discharging openings, said pistons during movement to the discharge opening being spaced to define therebetween an article receiving and conveying chamber selectively alternately registrable with said loading and discharging openings, one of said pistons being powered and the other being freely slidable, and connector means carried on one of the pistons for selective coupling engagement with the other piston in one direction of said reciprocal movement.

2. The device of claim 1 in which said connector means comprises an electromagnet.

3. The device of claim 1 in which said connector means includes an extendible hook member on one of said pistons, and a selectively rotatable hook receiving member mounted on the other of said pistons.

4. The device of claim 1 in which said articles comprise non-buoyant containers to provide a substantially rigid force transmitting member when disposed within said chamber between said pistons and being perforate so that the buoyancy of the material therein is effective to float such containers to the surface of the column of liquid.

5. The device of claim 1 in which said containers are imperforate and provide a non-buoyant material receiving compartment and a gas-filled flotation compartment capable of floating containers to the surface of said column of liquid with the non-buoyant material therein.

6. An article elevating device for buoyant articles comprising an elongated tubular casing; a column of liquid within the casing having opposite upper and lower ends; article loading means providing a circular tube providing a cylindrical passage having closed opposite ends extending substantially transversely through said casing and column of liquid in downwardly spaced relation from said upper end thereof; a plurality of cylindrical article actuating slugs slidably disposed within said passage of the tube in substantially end-to-end abutting relation, said tube providing spaced opposite ends within said casing to define an article discharging opening therebetween within said column of liquid; an article loading opening through the tube in outwardly spaced relation from said casing; said slugs being spaced adjacent to the column of liquid to provide article receiving chambers in precise registry with said loading and discharging openings in the tube; and a powered article and slug actuating finger reciprocably mounted on and extended into said tube ahead of said loading opening successively to engage and move articles from said loading opening to said discharging opening for automatic release therefrom upwardly into said column of liquid.

7. The device of claim 6 in which said casing at said lower end of the column of liquid has a collector floor below said tube for receiving non-buoyant articles from said discharging opening, and an access door adjacent to said floor for removing said non-buoyant articles after draining said column of liquid from the casing.

8. An article elevating device for buoyant articles comprising a substantially erect casing having upper and lower ends, a flotation fluid in the casing, tubular means mounted substantially horizontally in the lower end of the casing having an article loading opening externally of the casing and an article discharge opening internally of the casing immersed in said fluid, first and second plungers fitted to the tubular means and movable therein, and means for successively positioning the plungers in a first position disposed in spaced relation on opposite sides of the loading opening to receive such an article therebetween and with the first plunger blocking fluid flow through the tubular means from the casing to the loading opening, in a second position disposed on opposite sides of the discharge opening to release the article through said opening and with the second plunger disposed between said openings blocking fluid flow through the tubular means from the casing to the loading opening and with the first plunger in endward abutment with the second plunger to exclude fluid from therebetween and return to the first position, one of said plungers being freely slidable, and the positioning means having powered connection to the other of said plungers and including connector means carried by one of said plungers coupling the plungers for corresponding movement when the plunger with the powered connection moves in a direction away from the freely slidable plunger and releasing the plungers when the plunger with the powered connection moves in a direction toward the freely slidable plunger. 

1. An article elevating device for buoyant articles comprising a column of liquid having predetermined upper and lower ends; and means downwardly spaced from said upper end of the column for successively injecting such articles into the column of liquid for ascent through the liquid to the upper end of the column, said means including a valve having an article loading opening outwardly spaced from said column of liquid and an article discharge opening disposed within the column of liquid with the valve continually closing the column to block leakage of liquid therefrom during injection of said articles, a pair of slidably mounted pistons reciprocable between said article loading and article discharging openings, said pistons during movement to the discharge opening being spaced to define therebetween an article receiving and conveying chamber selectively alternately registrable with said loading and discharging openings, one of said pistons being powered and the other being freely slidable, and connector means carried on one of the pistons for selective coupling engagement with the other piston in one direction of said reciprocal movement.
 2. The device of claim 1 in which said connector means comprises an electromagnet.
 3. The device of claim 1 in which said connector means includes an extendible hook member on one of said pistons, and a selectively rotatable hook receiving member mounted on the other of said pistons.
 4. The device of claim 1 in which said articles comprise non-buoyant containers to provide a substantially rigid force transmitting member when disposed within said chamber between said pistons and being perforate so that the buoyancy of the material therein is effective to float such containers to the surface of the column of liquid.
 5. The device of claim 1 in which said containers are imperforate and proviDe a non-buoyant material receiving compartment and a gas-filled flotation compartment capable of floating containers to the surface of said column of liquid with the non-buoyant material therein.
 6. An article elevating device for buoyant articles comprising an elongated tubular casing; a column of liquid within the casing having opposite upper and lower ends; article loading means providing a circular tube providing a cylindrical passage having closed opposite ends extending substantially transversely through said casing and column of liquid in downwardly spaced relation from said upper end thereof; a plurality of cylindrical article actuating slugs slidably disposed within said passage of the tube in substantially end-to-end abutting relation, said tube providing spaced opposite ends within said casing to define an article discharging opening therebetween within said column of liquid; an article loading opening through the tube in outwardly spaced relation from said casing; said slugs being spaced adjacent to the column of liquid to provide article receiving chambers in precise registry with said loading and discharging openings in the tube; and a powered article and slug actuating finger reciprocably mounted on and extended into said tube ahead of said loading opening successively to engage and move articles from said loading opening to said discharging opening for automatic release therefrom upwardly into said column of liquid.
 7. The device of claim 6 in which said casing at said lower end of the column of liquid has a collector floor below said tube for receiving non-buoyant articles from said discharging opening, and an access door adjacent to said floor for removing said non-buoyant articles after draining said column of liquid from the casing.
 8. An article elevating device for buoyant articles comprising a substantially erect casing having upper and lower ends, a flotation fluid in the casing, tubular means mounted substantially horizontally in the lower end of the casing having an article loading opening externally of the casing and an article discharge opening internally of the casing immersed in said fluid, first and second plungers fitted to the tubular means and movable therein, and means for successively positioning the plungers in a first position disposed in spaced relation on opposite sides of the loading opening to receive such an article therebetween and with the first plunger blocking fluid flow through the tubular means from the casing to the loading opening, in a second position disposed on opposite sides of the discharge opening to release the article through said opening and with the second plunger disposed between said openings blocking fluid flow through the tubular means from the casing to the loading opening and with the first plunger in endward abutment with the second plunger to exclude fluid from therebetween, and return to the first position, one of said plungers being freely slidable, and the positioning means having powered connection to the other of said plungers and including connector means carried by one of said plungers coupling the plungers for corresponding movement when the plunger with the powered connection moves in a direction away from the freely slidable plunger and releasing the plungers when the plunger with the powered connection moves in a direction toward the freely slidable plunger.
 9. The device of claim 8 in which the connector means is electromagnetic.
 10. The device of claim 8 in which the connector means includes a hook member on one of said plungers and a releasable receiving member on the other of said plungers. 